Fiber-optics allow information to be transmitted through an optical link (such as optical fiber) as pulses of light. The light forms an electromagnetic carrier wave that can be modulated to carry data, control signals, and other information. Optical links have significantly higher bandwidths and are less susceptible to electromagnetic interference than conventional electrical cabling (such as copper wires and Ethernet cables), and are often used to transmit data over relatively long distances. Optical transmitters may be used to convert electrical signals into optical signals suitable for transmission via optical links, and optical receivers may be used to convert optical signals into electrical signals suitable for transmission via conventional electrical cabling.
The conversion of electrical signals to optical signals may be performed using a variety of electro-optical converters including, for example, electro-absorption modulators (EAMs) and ring modulators (RMs). Because optical signals typically have a voltage swing (such as between logic low and logic high states) greater than supply voltages used by CMOS-based circuits, optical drivers may be used to increase the voltage swing of electrical signals prior to their conversion to optical signals. As data rates continue to increase, it becomes more difficult for optical drivers to sustain increasingly faster logic state transitions of electrical signals while also increasing their voltage swings to higher levels suitable for optical signals.
Further, non-linear distortion caused by power amplifiers and other circuits within electro-optical converters may cause the electro-optical converters to exhibit asymmetric responses to rising and falling edges of the electrical signals to be converted to optical signals. These asymmetric responses may cause the converted optical signals to have different rise and fall times associated with logic state changes in data signals, which is undesirable.